This invention relates to transmission control systems and more particularly to manually operated transmission control mechanisms.
In column mounted shift control mechanisms which utilize cable members for a connection between the operator control and the transmission manual valve, there are two basic type systems. These systems can be referred to as concentric or linear shift type systems.
In the concentric shift type system, the shift mechanism is rotatable either about the axis of the steering column or an axis substantially parallel the steering column. The transmitter cable of the concentric type system is generally connected to an arm near the lower end of the steering column and from there routed to the transmission. Concentric shift mechanisms generally require a shift bowl, a long shift tube, mounting brackets and support bearings for supporting the shift tube for rotary movement within the brackets.
With linear shift type systems, the transmission shift cable is generally routed parallel to the steering column longitudinal axis and is connected to a member that is pivotally mounted for moving the cable in a substantially linear path.
Steering column mounted linear shift mechanisms disclosed in the prior art utilize a ball and cam system for transferring from the rotary motion of the shift lever to linear motion of the shift cable. An example of a system such as this is shown in U.S. Pat. No. 4,733,573 issued Mar. 29, 1988, to Kramer and assigned to the assignee of the present invention. It should be noted that with this linear shift mechanism, the manual shift lever is rotatable about the longitudinal axis of the steering column. The linear shift system eliminates the long shift tube utilized with the concentric system and replaces it with a cam driver mechanism which can introduce lash into the system and can require intricate assembly.